EP2097635A1

EP2097635A1 - Fuel injection valve and fuel injection system

Info

Publication number: EP2097635A1
Application number: EP07820738A
Authority: EP
Inventors: Ingo Rettig; Martin Scheffel; Anh-Tuan Hoang; Martin Buehner; Andreas Eckbauer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-11-30
Filing date: 2007-10-01
Publication date: 2009-09-09
Anticipated expiration: 2027-10-01
Also published as: WO2008064941A1; JP2010511121A; EP2097635B1; KR101423997B1; DE102006056704A1; KR20090083914A; CN101542105A; JP5065405B2; US7886717B2; CN101542105B; ATE458142T1; DE502007002889D1; US20090260597A1

Abstract

A fuel injector, especially for the direct injection of fuel into a combustion chamber of an internal combustion engine, includes a nozzle body able to be inserted into a recess of a cylinder head, a valve housing, a plug abutting the valve housing, and at least one fixation element, which fixes the nozzle body in its position in the recess, the fixation element extending from a connection region (28) between the valve housing and the plug on the spray-discharge side. The at least one fixation element has a reinforcement having a spherical contour at an outer periphery, the reinforcement being formed by at least one outwardly projecting element having an outwardly curving end face and/or having a planar end face.

Description

title

Fuel injector and fuel injection system

State of the art

The invention relates to a fuel injection valve according to the preamble of claim 1 and of a fuel injection system according to the preamble of claim 12.

Since only a few high-pressure injection valves spray the fuel jet actually in the extension of the valve longitudinal axis, but usually the spray is inclined to the longitudinal axis of the valve, which also in multi-hole valves, the injection holes are arranged predominantly asymmetric, it is important, the high-pressure injection valve in the cylinder head, in which it is used to fix so that no rotation of the valve can take place and the spray angle always corresponds to the interpretation.

For example, known solutions for fixing a high-pressure injection valve in a cylinder head include providing a rib at a portion of the outer circumference of the valve body which is inserted into the cylinder head, which then engages in a correspondingly provided in the cylinder head groove. For this purpose, however, it is necessary that the groove must be milled in accordance with the cylinder head. In addition, in the area in which the rib engages in the milled groove, for reasons of space no insertion bevels can be attached, which facilitate insertion of the valve when installed in the cylinder head. Due to the lack of these chamfers, the assembly of the high-pressure injection valve into the cylinder head is made more difficult and an assembly of a FCA, ie a rail, in which several valves are already mounted, then all high-pressure injection valves are mounted with the rail simultaneously in the cylinder head are even almost impossible or at least not suitable for series production, since during assembly all valves must be re-aligned according to their position.

Another solution for positionally fixing a high-pressure injection valve in a cylinder head provides the known use of a hold-down, which then passes the position to the rail and the cylinder head.

However, a transfer of the position from the high-pressure injection valve on the hold-down and then on the rail is only possible if the use of a corresponding hold-down is possible and on the rail a corresponding milling, in this case, a wrench size attached.

In DE 197 35 665 Al, for example, a

Fuel injection system for direct injection of fuel into a combustion chamber of an internal combustion engine described, wherein a cylinder head for each fuel injection valve has a opening into the associated combustion chamber receiving bore for receiving the Abspritzabschnitts of the fuel injection valve. The receiving bore is formed there as a stepped bore and has a tapered portion on which a first sealing element sealingly abuts and the Abspritzabschnitt seals against the cylinder head. The fuel injection valve is pivotably mounted on the first designed as an O-ring seal member so that it is slightly tilted within predetermined limits by a solid angle OC. The arrangement described in DE 197 35 665 Al allows pivoting of the fuel injection valve relative to the longitudinal axis within the solid angle range OC, wherein a sufficient hold-down force can be transmitted to the fuel injection valve by a clamping claw in the entire pivoting range. By tightening the clamping screws Spannspatzen, which are screwed into the cylinder head, the fuel injection valves are rigidly fixed to the cylinder head. A disadvantage of all known from the prior art solutions for fixing the high-pressure injection valve, however, is that associated with their implementation expensive milling processes.

Advantages of the invention

In contrast, the fuel injection valve according to the invention with the characterizing feature of claim 1 and the fuel injection system according to the invention with the characterizing feature of independent claim 12 have the advantage that a cost-effective solution for fixing the fuel injection valve in a cylinder head is made possible on the one hand sufficient insertion bevels for a problem-free installation allows the individual high-pressure injection valves and a FCAs and on the other hand ensures accurate positioning of the valve.

According to the invention a fixing element is provided, which fixes the nozzle body in its position in the first recess, and which is formed in the form of a thickening with spherical contour. The fixing element has outwardly curved end surfaces and / or plane end surfaces. The cylinder head has a corresponding second recess, in which the fixing element can be inserted, in the form of a slot. The fixing element may preferably z. Example, be provided as a molded pin on the outer periphery of the valve housing, which then engages in the bore or recess in the cylinder head (or in the rail) and thus fixes the fuel injection valve securely in position.

The longitudinal axis of the fixing element is provided substantially coaxially with the longitudinal axis of the fuel injection valve.

Preferably, the convex contour of the fixing element has an undercut above the convex contour, so that a tilting of this Verdrehfixierung in the form of the fixing and thus breaking it is prevented. It is also particularly advantageous if the Verdrehfixierung in the form of the fixing below the convex contour downwards, ie in the direction of the discharge end of the fuel injection valve, tapers to provide a so-called insertion bevel to facilitate the mounting of the high-pressure injection valve.

If the fuel injector is not mounted by default with an intermediate sleeve to the rail, which acts as a compensation element, the provision of the slot or the one-sided open slot in the cylinder head is particularly advantageous. For tolerance compensation between the rail cup and the cylinder head bore, the high-pressure injection valve must be slightly inclined. This inclination causes a movement in the Verdrehfixierung. Therefore, it is important that there is sufficient space in the radial direction, so that the radial movement of the valve by the tolerance compensation does not lead to a transverse force (strain) on the Verdrehfixierung or on the fixing.

This can be achieved by the recess or bore in the cylinder head is executed around, but has a significantly larger diameter than the fixing element, which acts as Verdrehfixierung. However, this configuration would have a big game in the middle position and thus a large spray deviation. The execution of the recess or hole as a slot is in contrast particularly advantageous because the necessary mounting clearance between the cylinder head bore and the Verdrehfixierung is independent of the deflection between the rail cup and cylinder head bore. Thus, the assembly play between the cylinder head bore or recess and the Verdrehfixierung be kept constant and particularly small in the form of the fixing. Also, this type of design has a particularly favorable effect on the spray tolerances.

Furthermore, it is advantageous that the fuel injection valve is a multi-hole valve with asymmetrically arranged spray holes and that the sprayed through the injection holes fuel jet is inclined relative to the valve longitudinal axis.

Furthermore, it is advantageous if the bore or recess, in which engages the Verdrehfixierung or at least one fixing element, is designed as a one-sided open slot. This is particularly advantageous in tight spaces, because in this embodiment can be advantageously dispensed with the insertion.

Depending on the production method, the boundary of the recess can be designed, for example, with a radius or as an edge. Contours are also possible that can already be produced with the cast of the cylinder head.

drawing

An embodiment of a fuel injection valve according to the invention and a Kraftstoffein- injection system according to the invention and a fuel injection system according to the

Prior art is shown in simplified form in the drawing and will be explained in more detail in the following description. Show it:

1 shows a schematic cross section through a fuel injection valve with Verdrehfixierung.

Fig. 2 is a side view of the fixing element according to the invention;

Fig. 3a - 3d four sectional views of various

Embodiments of fixing elements;

Fig. 4 is a schematic partially sectioned side view of the fixing element according to the invention;

FIGS. 5a-5d show respective side views of a section of the fixing element with a spherical contour; 6a - 6c are respective sectional views of differently executed recesses in the cylinder head with associated plan views of the recesses; and

7a, 7b are sectional views of an embodiment of a

Verdrehfixierung in a round cylinder head bore or recess and in a slot formed as a slot.

Description of the embodiment

Fig. 1 shows a schematic cross section through a fuel injection valve 1. The fuel injection valve 1 in the form of a direct-injection fuel injection valve is installed in a cylinder head 2 of an internal combustion engine.

The fuel injection valve 1 has, at an inlet-side end 3, a plug-in connection to a fuel distributor line 4 which, through a seal 5 in the form of an O-ring between the

Fuel distribution line 4 and a supply pipe 6 of the fuel injection valve 1 is sealed. The

Fuel injection valve 1 has a plug 7 for the electrical contacting for actuating the fuel injection valve 1.

The fuel injection valve 1 has in a first recess 9 or receiving bore of the cylinder head 2 a washer 8, which serves as a compensation element for the fuel injection valve 1 in the receiving bore 9 and manufacturing tolerances of the individual components, such as the nozzle body 11 or a valve housing 13 as well as temperature-related tolerances compensated.

The nozzle body 11 has a sealing ring 12 plugged onto a discharge-side end. The fuel injection system shown here is an example at which the fuel injection valve 1 is not mounted with an intermediate sleeve to the fuel rail 4, but only a Dichtstellte between

Fuel distribution line 4 and fuel injection valve 1 in the form of an O-ring 5 are. Furthermore, this injects

Fuel injection valve 1 in the extension of a longitudinal axis 16 and is not inclined relative to this. A fixing element 15 extends on the discharge side from a connection region 28 between the plug 7 and the valve housing 13. The fixing element 15 is in the form of a second recess or receiving bore 31 in the form of a fixing element

Blind hole added to the cylinder head 2. In this case, a longitudinal axis 29 of the fixing element 15 extends coaxially to the longitudinal axis 16 of the nozzle body 11. At the outer periphery of the fixing element 15, a thickening in the form of four outwardly projecting members 30 is provided, which have a spherical contour. However, the number of outwardly projecting members 30 is variable. Thus, instead of four elements 30, for example, only two or even more than four may be provided. The fixing element 15 is injection-molded, for example, as part of a plastic encapsulation.

The housing 13 is provided with a plastic extrusion, which simultaneously forms the plug 7, on whose outer periphery an outwardly projecting fixing element 15 is formed, which forms a convex contour and as Verdrehfixierung of Valve in the cylinder head (not shown) is used. For reinforcement purposes, a rib 17 is also provided along the longitudinal axis 29 on the outer circumference of the fixing element 15, which is molded onto the fixing element 15.

The fixing element 15 or its convex contour and the radially outwardly of the fixing element 15 outwardly projecting elements 30 which form the thickening are formed such that at its upper inlet end an undercut 19 is provided and they leash in the discharge direction of the fuel injection valve

Insertion bevel 18 in the form of a continuous taper, which the assembly of the fuel injection valve. 1 facilitated. The undercut 19 at the upper end of the convex contour also prevents that after tilting 15 in the cylinder head bore or recess (not shown) tilted.

3a to 3d show respective sectional views along the line III-III of FIG. 2 of various embodiments of the Verdrehfixierungen invention or the fixing element 15th

Fig. 3a shows a Verdrehfixierung having four outwardly projecting members 30, which are provided in each case at 90 ° intervals on the outer periphery of the fixing element 15 and thus form four spherical contours and the thickening of this.

Fig. 3b shows an embodiment which also has four outwardly projecting elements 30, of which, however, each two opposing elements differ in the length with which they protrude from the fixing element 15 radially outward. The outwardly projecting end surfaces 20 of the fixing elements 15 are here in contrast to the embodiment shown in Fig. 3a plan formed, but may also have a curvature, so that a convex contour is provided.

Fig. 3c shows an embodiment in which only two outwardly projecting elements 30 are provided and the remaining outer surfaces of the fixing element 15, on which no outwardly projecting elements 30 are provided, may be of any desired design.

Finally, Fig. 3d shows an embodiment which is similar to that shown in Fig. 3a, but in addition to the outer periphery of the fixing member 15, a reinforcement in the form of a transverse rib 17 is provided.

In Fig. 4 is schematically the deviation of the longitudinal axis 29 of the

Fixing element 15 to the longitudinal axis 20 of the second recess 31 of the cylinder head 2, wherein the two longitudinal axes a Include angle α, which also the inclination of the

Fuel injection valve 1 between the pivot points of the position 23 of the O-ring 5 in the rail cup 21 and the position of the combustion chamber seal 22, for. in the form of a provided around the outer periphery of the nozzle body 11 sealing ring 12 (not shown) indicates. The Verdrehfixierung of the fuel injection valve 1 in the form of the fixing element 15 with spherical contour engages in the recess 31 a. By virtue of this configuration according to the invention, the rotational fixation in the recess 31 also inclines with a corresponding tolerance compensation. Had the Verdrehfixierung no spherical contour or no undercut above the convex contour, then the Verdrehfixierung or the fixing element 15 could tilt in the recess 31 and break under certain circumstances.

5a to 5d show various side views of a portion of the fixing element 15 which has various embodiments of Verdrehungenungen or outwardly projecting members 30 at its outer periphery.

In Fig. 5a, radially outwardly projecting members 30 are provided on the outer periphery of the fixing element 15, which have a spherical contour. At the lower end, the fixing element 15 has an insertion bevel 18.

In the embodiment shown in Fig. 5b, however, no insertion bevel 18 is provided and outwardly projecting elements 30 have a rounded shape.

FIG. 5 c shows an embodiment in which the outwardly projecting elements 30 are plan-shaped at their outer end faces 24 and not rounded as shown in FIG. 5 b and have respective undercuts 19 adjacent thereto and above the outer end faces 24.

FIG. 5 d shows a further exemplary embodiment, in which the outwardly projecting elements 30 have a convex contour, which is stretched in the direction of the longitudinal axis 29 of the fixing element 15 Undercut or have a recess 19 at the upper end.

6a to 6c respectively show sectional views of differently executed second recesses 31 in the cylinder head 2 with associated plan views of the second recesses 31. In FIG. 6a, the second recess 31 or cylinder head bore is made round, into which the rotational fixing of the fixing element 15 (not shown) engages. The second recess 31 must be formed significantly larger than the Verdrehfixierung to allow a radial movement of the fixing member 15 (not shown). The second recess 31 further has an upper hollow truncated cone-shaped portion 25 as an insertion bevel 18 and an adjoining hollow cylindrical portion 26. Fig. 6b shows a second recess 31, in which the

Verdrehfixierung (not shown) of the fixing member 15 engages, which is designed as a slot. It is particularly advantageous that the necessary assembly clearance between the cylinder head bore or recess 31 is independent of the deflection between the rail cup 21 and cylinder head bore 31.

Thus, the mounting clearance between the cylinder head bore 31 and the Verdrehfixierung can be kept constant and very small (see Fig. 7b).

Finally, Fig. 6c shows a further embodiment in which the second recess 31 is designed as a one-sided open slot. This is particularly advantageous in confined spaces, since it is possible to dispense with the insertion bevel 18. Depending on the manufacturing method, the boundary of the second recess 31 can be designed with a radius (indicated by the dashed line) or with a step 27 in an edged manner.

Fig. 7a and 7b show the different mounting game, which have formed on the fixing element 15 outwardly projecting elements 30 between a circular recess 31 and a slot 31 formed as a slot. As with the distance a shown, there is a large clearance in the center position, which results in a large spray deviation, and which is also not constant when the fuel injection valve 1 is in an inclined position, as indicated by the distance b. As can be seen here, the mounting play in the middle position is greater than in the inclined position. This is not the case when the recess 31 is formed as a slot (Fig. 7b). Here the assembly play, which is marked with the distance c, remains constant both in the middle position and in the inclined position.

Claims

claims

1. Fuel injection valve (1), in particular for the direct injection of fuel into a combustion chamber of a

Internal combustion engine which has a nozzle body (11) which can be inserted into a recess (9) of a cylinder head (2), a valve housing (13), a plug (7) adjoining the valve housing (13) and at least one fixing element (15) , which fixes the nozzle body (11) in its position in the recess (9), wherein the fixing element (15) extends from a connecting region (28) between the valve housing (13) and the plug (7) on the injection side, characterized in that the at least one fixing element (15) has a thickening on an outer circumference, wherein the thickening is formed by at least one outwardly projecting element (30) with an outwardly curved end surface (24) and / or with a planar end surface (24).

2. Fuel injection valve (1) according to claim 1, characterized in that the valve housing (13) with a plastic extrusion, which simultaneously forms the plug (7) is provided, wherein the

Fixing element (15) is integrally formed on the plastic extrusion.

3. Fuel injection valve (1) according to claim 1 or 2, characterized in that the fixing element (15) at its outer periphery two

Thickenings in the form of outwardly projecting members (30) formed on opposite sides on the fixing member (15).

4. Fuel injection valve (1) according to claim 2 or 3, characterized in that in that four outwardly projecting elements (30) are formed at intervals of 90 ° on the outer circumference of the fixing element (15).

5. Fuel injection valve (1) according to one of claims 2 to 4, characterized in that the at least one fixing element (15) is designed in the form of a molded pins.

6. Fuel injection valve (1) according to one of claims 1 to 5, characterized in that above the contour of the at least one outwardly projecting element (30) in the direction of the inlet end (3) of the fuel injection valve (1) an undercut (19) is provided is.

7. Fuel injection valve (1) according to one of claims 1 to 6, characterized in that the contour of the element (30) in the direction of the discharge-side end (14) of the fuel injection valve (1) continuously tapers.

8. Fuel injection valve (1) according to one of claims 2 to 7, characterized in that on the outer circumference of the fixing element (15) has a rib (17) is provided, which serves as a reinforcement.

9. Fuel injection valve (1) according to claim 8, characterized in that the fuel injection valve (1) is sealed against the rail cup (21) of a fuel distributor line (4) with an O-ring (5).

10. Fuel injection valve (1) according to one of claims 1 to 9, characterized in that the fuel injection valve (1) is a multi-hole valve with asymmetrically arranged spray holes.

11. Fuel injection valve (1) according to one of claims 1 to 10, characterized in that the ejected through the injection holes fuel jet is inclined relative to the valve longitudinal axis (16).

12. Fuel injection system (10), which a

Fuel injection valve (1) according to one of claims 1 to 11 and a cylinder head (2) with at least one recess (9) for receiving a nozzle body (11) of the fuel injection valve (1), characterized in that a second recess (31) in the Cylinder head (2) is provided for receiving a fixing element (15), which is designed in the form of a slot.

13. The fuel injection system (10) according to claim 12, characterized in that the slot is formed as a one-sided open slot.

14, fuel injection system (10) according to claim 12 or 13, characterized in that the second recess (31) for providing an insertion bevel (18) in at least one portion (25) is formed frustoconical.

15. Fuel injection system (10) according to any one of claims 12 to 14, characterized in that the second recess (31) in at least one portion (26) is formed as a hollow cylinder.

16. Fuel injection system (10) according to any one of claims 12 to 15, characterized the fuel injection valve (1) is connected at its inlet-side end (3) to a rail cup (21) of a fuel distributor line (4).

17. Fuel injection system (10) according to any one of claims 12 to

16, characterized in that the at least one fixing element (15) with the inner wall of the second recess (31) is engaged.